Send tracks to listenbrainz

[elamperti]

Describe the solution you'd like
Open Scrobbler should be able to push tracks to listenbrainz in the same way it currently scrobbles to last.fm.

Listenbrainz has a proxy compatible with last.fm, so it should be possible to reutilize significant parts of the current code (but it requires new logic to handle this split).

Describe alternatives you've considered
Users currently have to manually import/update their listenbrainz profile using lastfm data.

Additional context
Requested on Discord by asmLANG and k8vsy (permalink)